This work was partially supported by the College of Medicine, the Vice President for Research, UK HealthCare, and the Research Priority Area at the University of Kentucky as part of the College of Medicine Alliance Initiative and Dr. Jihye Bae&#39;s Start-Up funds provided by the Department of Electrical and Computer Engineering at the University of Kentucky. The authors thank the volunteer participants for the recording and the Epilepsy-Neuroimaging Research Alliance team members, especially Dr. Brian Gold for leading the alliance team, Dr. Sridhar Sunderam for research mentorship, and Susan V. Hollar and Emily Ashcraft for patient care and management.

<ol>
	<li>Ngugi, A. K., Bottomley, C., Kleinschmidt, I., Sander, J. W., Newton, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimation+of+the+burden+of+active+and+life-time+epilepsy:+a+meta-analytic+approach.">Estimation of the burden of active and life-time epilepsy: a meta-analytic approach.</a> Epilepsia. 51 (5), 883-890 (2010).</li><li>Kwan, P., Brodie, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+Identification+of+refractory+epilepsy.">Early Identification of refractory epilepsy.</a> The New England Journal of Medicine. 342 (5), 314-319 (2000).</li><li>Menon, V., Crottaz-Herbette, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combined+EEG+and+fMRI+studies+of+human+brain+function.">Combined EEG and fMRI studies of human brain function.</a> International Review of Neurobiology. 66, 291-321 (2005).</li><li>Gotman, J., Pittau, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combining+EEG+and+fMRI+in+the+study+of+epileptic+discharges.">Combining EEG and fMRI in the study of epileptic discharges.</a> Epilepsia. 52, 38-42 (2011).</li><li>Pittau, F., Dubeau, F., Gotman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contribution+of+EEG/fMRI+to+the+definition+of+the+epileptic+focus.">Contribution of EEG/fMRI to the definition of the epileptic focus.</a> Neurology. 78 (19), 1479-1487 (2012).</li><li>Ikemoto, S., von Ellenrieder, N., Gotman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electroencephalography-functional+magnetic+resonance+imaging+of+epileptiform+discharges:+Noninvasive+investigation+of+the+whole+brain.">Electroencephalography-functional magnetic resonance imaging of epileptiform discharges: Noninvasive investigation of the whole brain.</a> Epilepsia. 63 (11), 2725-2744 (2022).</li><li>Mullinger, K. J., Castellone, P., Bowtell, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Best+current+practice+for+obtaining+high+quality+EEG+data+during+simultaneous+fMRI.">Best current practice for obtaining high quality EEG data during simultaneous fMRI.</a> Journal of Visualized Experiments. (76), e50283 (2013).</li><li>Douglas, P. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+for+simultaneous+fMRI/EEG+data+collection+during+a+focused+attention+suggestion+for+differential+thermal+sensation.">Method for simultaneous fMRI/EEG data collection during a focused attention suggestion for differential thermal sensation.</a> Journal of Visualized Experiments. (83), e3298 (2014).</li><li>Nguyen, T., Potter, T., Karmonik, C., Grossman, R., Zhang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concurrent+EEG+and+functional+MRI+recording+and+integration+analysis+for+dynamic+cortical+activity+imaging.">Concurrent EEG and functional MRI recording and integration analysis for dynamic cortical activity imaging.</a> Journal of Visualized Experiments. (136), e56417 (2018).</li><li>Khoo, H. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reliable+acquisition+of+electroencephalography+data+during+simultaneous+electroencephalography+and+functional+MRI.">Reliable acquisition of electroencephalography data during simultaneous electroencephalography and functional MRI.</a> Journal of Visualized Experiments. (169), e62247 (2021).</li><li>Allen, P. J., Josephs, O., Turner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+removing+imaging+artifact+from+continuous+EEG+recorded+during+functional+MRI.">A method for removing imaging artifact from continuous EEG recorded during functional MRI.</a> Neuroimage. 12 (2), 230-239 (2000).</li><li>Smith, S. J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+in+the+diagnosis,+classification,+and+management+of+patients+with+epilepsy.">EEG in the diagnosis, classification, and management of patients with epilepsy.</a> Journal of Neurology, Neurosurgery, and Psychiatry. 76, 2-7 (2005).</li><li>Manganotti, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous+EEG-fMRI+in+patients+with+partial+epilepsy+and+focal+interictal+slow-wave+discharges+on+EEG.">Continuous EEG-fMRI in patients with partial epilepsy and focal interictal slow-wave discharges on EEG.</a> Magnetic Resonance Imaging. 26 (8), 1089-1100 (2008).</li><li>Reiher, J., Beaudry, M., Leduc, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+intermittent+rhythmic+delta+activity+(TIRDA)+in+the+diagnosis+of+complex+partial+epilepsy:+sensitivity,+specificity+and+predictive+value.">Temporal intermittent rhythmic delta activity (TIRDA) in the diagnosis of complex partial epilepsy: sensitivity, specificity and predictive value.</a> The Canadian Journal of Neurological Sciences. 16 (4), 398-401 (1989).</li><li>Geyer, J. D., Bilir, E., Faught, R. E., Kuzniecky, R., Gilliam, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Significance+of+interictal+temporal+lobe+delta+activity+for+localization+of+the+primary+epileptogenic+region.">Significance of interictal temporal lobe delta activity for localization of the primary epileptogenic region.</a> Neurology. 52 (1), 202-205 (1999).</li><li>Koupparis, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Association+of+EEG-fMRI+responses+and+outcome+after+epilepsy+surgery.">Association of EEG-fMRI responses and outcome after epilepsy surgery.</a> Neurology. 97 (15), e1523-1536 (2021).</li><li>Gotman, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Has+recording+of+seizures+become+obsolete.">Has recording of seizures become obsolete.</a> Revue Neurologique. , 00865 (2023).</li><li>Pascual-Marqui, R. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Standardized+low-resolution+brain+electromagnetic+tomography+(sLORETA):+technical+details.">Standardized low-resolution brain electromagnetic tomography (sLORETA): technical details.</a> Methods and Findings in Experimental and Clinical Pharmacology. 24, 5-12 (2002).</li><li>Hallez, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+on+solving+the+forward+problem+in+EEG+source+analysis.">Review on solving the forward problem in EEG source analysis.</a> Journal of Neuroengineering and Rehabilitation. 4, 46 (2007).</li><li>Tadel, F., Baillet, S., Mosher, J. C., Pantazis, D., Leahy, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brainstorm:+a+user-friendly+application+for+MEG/EEG+analysis.">Brainstorm: a user-friendly application for MEG/EEG analysis.</a> Computational Intelligence and Neuroscience. 2011, 879716 (2011).</li><li>Srinivasan, R., Tucker, D. M., Murias, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+the+spatial+Nyquist+of+the+human+EEG.">Estimating the spatial Nyquist of the human EEG.</a> Behavior Research Methods, Instruments, &amp; Computers. 30, 8-19 (1998).</li><li>Michel, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+source+imaging.">EEG source imaging.</a> Clinical Neurophysiology. 115 (10), 2195-2222 (2004).</li><li>Abreu, R., Leal, A., Figueiredo, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG-informed+fMRI:+A+review+of+data+analysis+methods.">EEG-informed fMRI: A review of data analysis methods.</a> Frontiers in Human Neuroscience. 12, 29 (2018).</li><li>Saletu, B., Anderer, P., Saletu-Zyhlarz, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+topography+and+tomography+(LORETA)+in+the+classification+and+evaluation+of+the+pharmacodynamics+of+psychotropic+drugs.">EEG topography and tomography (LORETA) in the classification and evaluation of the pharmacodynamics of psychotropic drugs.</a> Clinical EEG Neuroscience. 37 (2), 66-80 (2006).</li><li>Windmann, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+midazolam+premedication+on+intraoperative+EEG+signatures+in+elderly+patients.">Influence of midazolam premedication on intraoperative EEG signatures in elderly patients.</a> Clinical Neurophysiology. 130 (9), 1673-1681 (2019).</li><li>Nishida, M., Zestos, M. M., Asano, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spatial-temporal+patterns+of+electrocorticographic+spectral+changes+during+midazolam+sedation.">Spatial-temporal patterns of electrocorticographic spectral changes during midazolam sedation.</a> Clinical Neurophysiology. 127 (2), 1223-1232 (2016).</li><li>Forsyth, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+local+spectral+modulation,+and+temporal+correlation,+of+simultaneously+recorded+EEG/fMRI+signals+during+ketamine+and+midazolam+sedation.">Comparison of local spectral modulation, and temporal correlation, of simultaneously recorded EEG/fMRI signals during ketamine and midazolam sedation.</a> Psychopharmacology. 235 (12), 3479-3493 (2018).</li></ol>

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

This experimental protocol is unique in providing a smooth transition of patients with epilepsy from the EMU to the scanning room, allowing it to be used in clinical and research settings. The use of FDA-approved MR conditional electrodes is an essential component for both clinical recordings during the time spent in the EMU and for safe transfer to MRI without having to remove or exchange the scalp electrodes from the patient. In the EMU, the MR conditional electrodes are connected to an amplifier for simultaneous video and EEG monitoring. For EEG-fMRI recordings, an MR conditional EEG amplifier and an MRI scanner can be used with a 20-channel head-coil, which accommodates the size of the electrode set and connecting wires. It must be noted that before conducting the simultaneous EEG-fMRI recordings in patients with epilepsy, a test run with a healthy subject is highly recommended to confirm the proper operation of all equipment and to become familiar with each required step.
In addition, concrete organization of the team and careful selection of patients also play a significant role in this protocol. To be viable for both clinical and research settings, it is required to have a structured team of epileptologists, nursing staff, EEG technologists, and engineers. For patient selection, the above-listed inclusion and exclusion criteria must be firmly considered.
Furthermore, it is important to address that when EEG-informed fMRI analysis is conducted, clear presence of the key features of EEGs must exist to guide the corresponding BOLD changes in fMRI. Therefore, when conducting the EEG-fMRI recording, it is important to consider patients who have previously demonstrated target EEG features. During the interictal period in patients with epilepsy, IEDs, which are abnormal and suggest epileptogenic potential, are a well-known EEG feature to reference to the BOLD changes16, even though the example here does not include this case. When targeting to obtain IEDs in the interictal EEG-fMRI recordings, experimenters should consider patients with frequent IEDs (at least three IEDs/hour) observed by a scalp EEG, in order to ensure sufficient epileptiform discharges during a scanning session. The number of IEDs can be determined from the EEG monitoring in the EMU, or from referencing the IED frequency seen in the subjects&#39; prior EEG recordings if they exist. The obtained recordings of interictal EEG-fMRI data can bring benefits to understanding and potentially localizing the seizure onset zone17.
Once a clean EEG is obtained after processing the artifact removal steps, further EEG analysis can be applied. For example, EEG source imaging (ESI) can be obtained by applying standardized low-resolution brain electromagnetic tomography (sLORETA)18 to estimate the brain&#39;s corresponding electrical activity on the cortical surface. The estimated sources can be obtained by inverting the computed lead field matrix based on the head, outer skull, inner skull, and cortex layers created from the patient&#39;s MRI using the boundary element method19. There are numerous publicly available toolboxes to obtain EEG source imaging, and Brainstorm is one popularly used MATLAB-based toolbox20.
When ESI is considered using the processed EEG, the total number of electrodes and their distributions must be carefully taken into account so that they can reasonably cover the entire head. The minimum number of electrodes necessary to implement ESI is 32 channels21,22, which is more than the standard number of electrodes used in clinical settings. Thus, it is recommended to include extra channels to cover the entire head with reasonable spacing. The channel selection in this study includes 21 channels, which are conventionally used in the clinic for EEG monitoring, and 11 additional channels to cover the head entirely (Figure 1).
Here, we do not include details of fMRI analysis, since this is out of the scope of our study. However, a possible direction is EEG-informed fMRI analysis23. For instance, the occurrence time of IEDs can be saved as event triggers to correlate with the fMRI, which can lead to a routine event-related fMRI analysis. In this case, a generalized linear model analysis can be used to find the brain regions showing changes in fMRI signal at the time of IEDs.
We point out that a recently published study10 has shown it is possible to use a carbon wire loop system when a more robust artifact removal technique is required16. However, we want to apprise that the integration of the carbon wire loop system in our experimental setting with the MR conditional electrode has not been investigated yet.
Even though this study specifically focuses on the interictal period of epilepsy, the introduced protocol for simultaneous EEG-fMRI can be further extended to the ictal or postictal period. However, specific considerations must be followed when any customized settings are considered. For the postictal phase, an important concern that we are cognizant of is that the patient is given a benzodiazepine prior to transport to the MRI. As for the frequency analysis of EEGs, it has been reported that benzodiazepines do not necessarily alter the specific frequency bands24,25, and in the case of modest changes, these are confined to the somatosensory-motor region26 or frontal lobes27. Furthermore, with respect to simultaneous EEG-fMRI, delta EEG-BOLD correlations showed no changes after benzodiazepine injection compared to a control with saline injection27. The BOLD signal was decreased in only the small areas of Heschel&#39;s gyrus and supplementary motor area.

Epilepsy afflicts nearly 70 million people worldwide1. As many as one out of every 150 people with poorly controlled epilepsy succumb to a sudden unexpected death in epilepsy (SUDEP) every year. Furthermore, roughly 30%-40% of epilepsy cases are refractory to medical management2. Neurosurgical treatment in the form of resection, disconnection, or neuromodulation can be a life-changing and life-saving measure for patients with refractory epilepsy.
Simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) is a unique combined technique that measures brain activities noninvasively, and has provided benefits for understanding and localizing seizure onset in epilepsy3,4,5,6. Scalp EEGs can be used to lateralize and localize seizure onset zones, but they have relatively poor spatial resolution due to limited capabilities with respect to assessing deep epileptogenic sources. While fMRI has good spatial resolution throughout the brain, including deep regions, fMRI alone is not specific to seizures. However, scalp EEGs can inform the interpretation of blood oxygen level-dependent (BOLD) activation or deactivation areas in fMRI, thereby producing an fMRI technique that is specific to epilepsy. Thus, the implementation of simultaneous EEG-fMRI can be used to map spatiotemporal processes relevant to localizing both the &#39;where&#39; and &#39;when&#39; of epileptic events.
Explanations of how to conduct simultaneous EEG-fMRI are provided in the previous studies7,8,9,10. However, EEG-fMRI has been underutilized in epilepsy, especially in clinical settings. There exists a study that provides a general procedure for EEG-fMRI recordings, background, and examples of possible EEG analysis7. Also, a study emphasizing hypnotic induction along with temperature measures in simultaneous EEG-fMRI recordings has been conducted8. Furthermore, an expanded EEG-fMRI study to introduce a spatiotemporal and fMRI-constrained EEG source imaging method has been proposed9,10. In addition, the use of a carbon wire loop to effectively remove artifacts from EEG-fMRI has been considered10. However, all these studies fail to address challenges in conducting EEG-fMRI studies in a clinical research setting. In particular, the use of the EEG cap restricts the feasibility of these protocols in clinical settings, and details about patient management are also missing. In this study, we provide an EEG-fMRI recording protocol that can be used in both clinical and research settings for patients with epilepsy. This unique protocol allows an easy patient transition from an epilepsy monitoring unit (EMU) to the scanning room. In addition, the protocol provides the potential to expand its application to postictal period recordings with epilepsy patients. For EEG-fMRI, post-processing is a crucial step in removing artifacts caused by MRI gradients and physiological artifacts, such as those related to heartbeat. Thus, we also provide step-by-step procedures to remove EEG artifacts using a standard template removal method11 for clinical review.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>3T Magnetom Prisma fit MRI scanner</td>
			<td>Siemens Healthineers</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Abralyt HiCl, 10 g.</td>
			<td>EASYCAP GmbH</td>
			<td></td>
			<td>Conductive gel for ECG electrode.</td>
		</tr>
		<tr>
			<td>BrainAmp MR plus 32-channel</td>
			<td>Brain Products GmbH</td>
			<td>S-BP-01300</td>
			<td></td>
		</tr>
		<tr>
			<td>BrainVision Analyzer Version 2.2.0.7383</td>
			<td>Brain Products GmbH</td>
			<td></td>
			<td>EEG analysis software.</td>
		</tr>
		<tr>
			<td>BrainVision Interface Box 32 inputs</td>
			<td>Ives EEG Solutions, LLC</td>
			<td>BVI-32</td>
			<td></td>
		</tr>
		<tr>
			<td>BrainVision Recorder License with dongle</td>
			<td>Brain Products GmbH</td>
			<td>S-BP-170-3000</td>
			<td></td>
		</tr>
		<tr>
			<td>BrainVision Recorder Version 1.23.0003</td>
			<td>Brain Products GmbH</td>
			<td></td>
			<td>EEG recording software.</td>
		</tr>
		<tr>
			<td>Collodion (non-flexible)</td>
			<td>Mavidon</td>
			<td></td>
			<td>Glue to secure EEG electrodes.</td>
		</tr>
		<tr>
			<td>Fiber Optic cable (30m one line)</td>
			<td>Brain Products GmbH</td>
			<td>S-BP-345-3020</td>
			<td></td>
		</tr>
		<tr>
			<td>Gold Cup Electrode set, 32 channel</td>
			<td>Ives EEG Solutions, LLC</td>
			<td>GCE-32</td>
			<td>2+ items are recommended when managing multiple subjects with overlapped/close period of Epilepsy Monitoring Unit (EMU) stay.</td>
		</tr>
		<tr>
			<td>Gold Cup Electrodes</td>
			<td>Ives EEG Solutions, LLC</td>
			<td>GCE-EKG</td>
			<td></td>
		</tr>
		<tr>
			<td>Harness, 32 lead, reusable</td>
			<td>Ives EEG Solutions, LLC</td>
			<td>HAR-32</td>
			<td>2+ items are recommended when managing multiple subjects with overlapped/close period of&#160; Epilepsy Monitoring Unit (EMU) stay.</td>
		</tr>
		<tr>
			<td>MR-sled kit including 100% and 75% length base plates, low profile (3 cm) block legs for each base plate, ramp, and strap systems as hand configured</td>
			<td>Brain Products GmbH</td>
			<td>BV-79123-PRISMA SKYRA</td>
			<td></td>
		</tr>
		<tr>
			<td>Natus NeuroWorks EEG</td>
			<td>Natus</td>
			<td></td>
			<td>Software used for EEG monitoring at the Epilepsy Monitoring Unit (EMU).</td>
		</tr>
		<tr>
			<td>Nuprep Skin Prep Gel</td>
			<td>Weaver and Co.</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Passive starter set, including consumables (gel, syringes, dispensing tips, adhesive washers, etc.) to facilitate out of the box data acquisition</td>
			<td>Brain Products GmbH</td>
			<td>S-C-5303</td>
			<td></td>
		</tr>
		<tr>
			<td>SyncBox compl. Extension box for phase sync recordings</td>
			<td>Brain Products GmbH</td>
			<td>S-BP-02675</td>
			<td>Syncbox</td>
		</tr>
		<tr>
			<td>syngo MR XA30</td>
			<td>Siemens Healthineers</td>
			<td></td>
			<td>Software used for the MRI scanner.</td>
		</tr>
		<tr>
			<td>Ten 20 Conductive Neurodiagnostic Electrode Paste</td>
			<td>Weaver and Co.</td>
			<td></td>
			<td>Conductive gel for EEG electrodes.</td>
		</tr>
		<tr>
			<td>TriggerBox Kit for BrainAmp</td>
			<td>Brain Products GmbH</td>
			<td>S-BP-110-9010</td>
			<td>Triggerbox; This Kit allows to expand the trigger width from the scanner so that the trigger signal can be detected on the BrainVision Recorder properly. This kit may not be required depending on the characteristics of the trigger signal provided by the scanner.</td>
		</tr>
		<tr>
			<td>Xltek EMU40EX amplifier</td>
			<td>Natus</td>
			<td></td>
			<td>An amplifier used at the Epilepsy Monitoring Unit (EMU).</td>
		</tr>
	</tbody>
</table>

equipment setup and artifact removal for simultaneous electroencephalogram and functional magnetic resonance imaging for clinical review in epilepsy

Simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) is a unique combined technique that provides synergy in the understanding and localization of seizure onset in epilepsy. However, reported experimental protocols for EEG-fMRI recordings fail to address details about conducting such procedures on epilepsy patients. In addition, these protocols are limited solely to research settings. To fill the gap between patient monitoring in an epilepsy monitoring unit (EMU) and conducting research with an epilepsy patient, we introduce a unique EEG-fMRI recording protocol of epilepsy during the interictal period. The use of an MR conditional electrode set, which can also be used in the EMU for a simultaneous scalp EEG and video recording, allows an easy transition of EEG recordings from the EMU to the scanning room for concurrent EEG-fMRI recordings. Details on the recording procedures using this specific MR conditional electrode set are provided. In addition, the study explains step-by-step EEG processing procedures to remove the imaging artifacts, which can then be used for clinical review. This experimental protocol promotes an amendment to the conventional EEG-fMRI recording for enhanced applicability in both clinical (i.e., EMU) and research settings. Furthermore, this protocol provides the potential to expand this modality to postictal EEG-fMRI recordings in the clinical setting.

When a patient is admitted to the EMU, a simultaneous scalp EEG and video are recorded. One purpose of the EEG monitoring by a neurologist is to evaluate for epileptiform discharges, which can potentially inform the localization of the seizure onset. When extraordinary dynamics of specific EEG channels are distinguished, the electrode locations can be associated with seizure localization. During the interictal period, interictal epileptiform discharges (IEDs), including spikes and sharp waves, are traditionally considered as markers of areas of epileptogenicity. Furthermore, the obtained recordings of interictal EEG-fMRI data can be advantageous to understand and localize the seizures. To validate this EEG-fMRI recording and EEG processing protocol, we evaluate the quality of the EEG by comparing the postprocessed EEG to the one from the EMU, and we confirm that the same distinguishable EEG characteristic is observed in both cases.
Focal delta slow activity is typically suggestive of an underlying brain structural lesion or an area where the neurons are not functioning as expected, which is often observed after strokes, head injuries, brain infections, or dementia. However, it is not uncommon for patients with focal epilepsy to demonstrate focal delta activity near or at the site of their epileptogenic zone. In addition, although focal delta activity is less specific than IEDs, it can specify localized structural pathology corresponding to seizure onset in epilepsy12. Furthermore, focal interictal slow waves in EEGs correspond to focal BOLD activation on fMRI that matches the epileptogenic area in patients with partial epilepsy13.
It is notable that, in temporal lobe onset epilepsy, a type of delta activity called temporal intermittent rhythmic delta (TIRDA) is sometimes present, and it is considered an IED equivalent14. On the contrary, temporal intermittent polymorphic delta (TIPDA) is not considered an IED equivalent15. In the processed EEG data, clear focal left temporal slow waves (TIPDA) are present, which is observed from the EEG recorded at the EMU (Figure 7). Although this delta activity is not IED equivalent, it suggests left temporal neuronal dysfunction.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/64919/64919fig01.jpg" /> 
Figure 1: An example of 32 electrode selections for simultaneous EEG-fMRI recording. In the clinic, 21 channels are commonly considered for EEG monitoring. To fulfill a minimum number of electrodes to conduct EEG source imaging (ESI), 11 additional channels are included to cover the head entirely. All electrodes are gold cups to avoid MR effects. In the figure, different colors are used to distinguish different electrodes, and the colors match the physical cable colors. Each rectangular box in the bottom indicates one junction to be connected to a harness, which will be connected to an amplifier for recording. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/64919/64919fig02.jpg" /> 
Figure 2: Electrode placements. (A) Placement of the electrodes on the patient&#39;s scalp and (B) arrangement of the cable junctions. The left images in (A) and (B) provide a top-front view, and the right images provide a left-side view of the patient. The red arrows in (B) indicate the placement of gauze pads. This helps to avoid imaging artifacts. The areas circled in blue in (B) show how the cable junctions are arranged. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/64919/64919fig03.jpg" /> 
Figure 3: Equipment connection in the monitoring room. (A) An overview of the USB 2 adapter, Syncbox, and Triggerbox connection. Detailed picture of (B) the USB 2 adapter and Syncbox cable connections, (C) the Syncbox and the fiber optic cable connection, and (D) the cable connections in the Triggerbox. The star marks on (B), (C), and (D) show the location of the USB cables to be connected to the recording PC. A schematic diagram of the EEG recording system and the connections required between the hardware is provided in Figure 1 in Mullinger et al.7. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/64919/64919fig04.jpg" /> 
Figure 4: Equipment connection in the scanning room. (A) An overview of the EEG amplifier connection in the scanner. (B) Wrapped cables from the interface box to connect the EEG electrodes (the red cable is for the ECG measure). (C) Connection of the interface box and the EEG amplifier and MR safe sandbags placed to reduce MR artifacts. (D) Connection of the amplifier (top) and the battery (bottom) and connection of the fiber optic cable from the Syncbox in the monitoring room to the amplifier. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/64919/64919fig05.jpg" /> 
Figure 5: Screenshot of workspace settings on the EEG recording software. The number of channels and sampling rate can be set under the amplifier settings. In addition, the specification of each channel can be modified, if necessary, by clicking the table at the bottom. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/64919/64919fig06.jpg" /> 
Figure 6: EEG artifact removal pipeline with representative examples. The raw EEG traces are displayed in the bottom left. The bottom middle plot shows EEG traces after applying MR artifact correction and a high pass filter of 0.5 Hz on the raw EEG. The bottom right plot displays EEG traces after applying CB artifact correction and a notch filter of 60 Hz on the processed EEG. The EEG traces are displayed under common ground mode to effectively visualize how each process influences each recorded channel. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/64919/64919fig07.jpg" /> 
Figure 7: Comparison of the processed EEG from a simultaneous EEG-fMRI recording (left) and an EEG recorded at the EMU (right). The red circle indicates focal left temporal slow waves at the same channels. The EEG traces are displayed in a double banana format, which is traditionally considered in the clinic. <a href="https://www.jove.com/files/ftp_upload/64919/64919fig07large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Equipment Setup and Artifact Removal for Simultaneous Electroencephalogram and Functional Magnetic Resonance Imaging for Clinical Review in Epilepsy at JoVE.c

Equipment Setup and Artifact Removal for Simultaneous Electroencephalogram and Functional Magnetic Resonance Imaging for Clinical Review in Epilepsy

This article details simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) recording procedures that can be used in both clinical and research settings. EEG processing procedures to remove imaging artifacts for clinical review are also included. This study focuses on the example of epilepsy during the interictal period.

Simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) is a unique combined technique that provides synergy in the ...

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Research

JoVE Journal

Bioengineering

1.7K Views.  University of Kentucky. This article details simultaneous electroencephalogram and functional magnetic resonance imaging (EEG-fMRI) recording procedures that can be used in both clinical and research settings. EEG processing procedures to remove imaging artifacts for clinical review are also included. This study focuses on the example of epilepsy during the interictal period.

Video: Equipment Setup and Artifact Removal for Simultaneous Electroencephalogram and Functional Magnetic Resonance Imaging for Clinical Review in Epilepsy

Magnetic Resonance Elastography Methodology for the Evaluation of Tissue Engineered Construct Growth

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use of destructive assessment is not acceptable. A proposed alternative is the use of an imaging process called magnetic resonance elastography. Elastography is a nondestructive method for determining the engineered outcome by measuring local mechanical property values (i.e., complex shear modulus), which are essential markers for identifying the structure and functionality of a tissue. As a noninvasive means for evaluation, the monitoring of engineered constructs with imaging modalities such as magnetic resonance imaging (MRI) has seen increasing interest in the past decade1. For example, the magnetic resonance (MR) techniques of diffusion and relaxometry have been able to characterize the changes in chemical and physical properties during engineered tissue development2. The method proposed in the following protocol uses microscopic magnetic resonance elastography (&mu;MRE) as a noninvasive MR based technique for measuring the mechanical properties of small soft tissues3. MRE is achieved by coupling a sonic mechanical actuator with the tissue of interest and recording the shear wave propagation with an MR scanner4. Recently, &mu;MRE has been applied in tissue engineering to acquire essential growth information that is traditionally measured using destructive mechanical macroscopic techniques5. In the following procedure, elastography is achieved through the imaging of engineered constructs with a modified Hahn spin-echo sequence coupled with a mechanical actuator. As shown in Figure 1, the modified sequence synchronizes image acquisition with the transmission of external shear waves; subsequently, the motion is sensitized through the use of oscillating bipolar pairs. Following collection of images with positive and negative motion sensitization, complex division of the data produce a shear wave image. Then, the image is assessed using an inversion algorithm to generate a shear stiffness map6. The resulting measurements at each voxel have been shown to strongly correlate (R2&gt;0.9914) with data collected using dynamic mechanical analysis7. In this study, elastography is integrated into the tissue development process for monitoring human mesenchymal stem cell (hMSC) differentiation into adipogenic and osteogenic constructs as shown in Figure 2.

The procedure demonstrates the methodology of magnetic resonance elastography for monitoring the engineered outcome of adipose and osteogenic tissue engineered constructs through noninvasive local assessment of the mechanical properties using microscopic magnetic resonance elastography (&mu;MRE).

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use ...

Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging

X-ray fluoroscopy-guided endovascular procedures have several significant limitations, including difficult catheter navigation and use of ionizing radiation, which can potentially be overcome using a magnetically steerable catheter under MR guidance.
	The main goal of this work is to develop a microcatheter whose tip can be remotely controlled using the magnetic field of the MR scanner. This protocol aims to describe the procedures for applying current to the microcoil-tipped microcatheter to produce consistent and controllable deflections.
	A microcoil was fabricated using laser lathe lithography onto a polyimide-tipped endovascular catheter. In vitro testing was performed in a waterbath and vessel phantom under the guidance of a 1.5-T MR system using steady-state free precession (SSFP) sequencing. Various amounts of current were applied to the coils of the microcatheter to produce measureable tip deflections and navigate in vascular phantoms.
	The development of this device provides a platform for future testing and opportunity to revolutionize the endovascular interventional MRI environment.

Current applied to an endovascular microcatheter with microcoil tip made by laser lathe lithography can achieve controllable deflections under magnetic resonance (MR) guidance, which may improve speed and efficacy of navigation of vasculature during various endovascular procedures.

X-ray fluoroscopy-guided  endovascular procedures have several significant limitations, including  difficult catheter navigation and use of ionizing ...

Universal Hand-held Three-dimensional Optoacoustic Imaging Probe for Deep Tissue Human Angiography and Functional Preclinical Studies in Real Time

The exclusive combination of high optical contrast and excellent spatial resolution makes optoacoustics (photoacoustics) ideal for simultaneously attaining anatomical, functional and molecular contrast in deep optically opaque tissues. While enormous potential has been recently demonstrated in the application of optoacoustics for small animal research, vast efforts have also been undertaken in translating this imaging technology into clinical practice. We present here a newly developed optoacoustic tomography approach capable of delivering high resolution and spectrally enriched volumetric images of tissue morphology and function in real time. A detailed description of the experimental protocol for operating with the imaging system in both hand-held and stationary modes is provided and showcased for different potential scenarios involving functional and molecular studies in murine models and humans. The possibility for real time visualization in three dimensions along with the versatile handheld design of the imaging probe make the newly developed approach unique among the pantheon of imaging modalities used in today&#8217;s preclinical research and clinical practice.

We provide herein a detailed description of the experimental protocol for imaging with a newly developed hand-held optoacoustic (photoacoustic) system for three-dimensional functional and molecular imaging in real time. The demonstrated powerful performance and versatility may define new application areas of the optoacoustic technology in preclinical research and clinical practice.

The exclusive combination of high optical contrast and excellent spatial resolution makes optoacoustics (photoacoustics) ideal for simultaneously ...

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan electron-paramagnetic-resonance (RS-EPR), which can provide quantitative information under in vivo conditions on oxygen concentration, pH, redox status and concentration of signaling molecules (i.e., OH&#8226;, NO&#8226;). The RS-EPR technique has a higher sensitivity, improved spatial resolution (1 mm), and shorter acquisition time in comparison to the standard continuous wave (CW) technique. A variety of phantom configurations have been tested, with spatial resolution varying from 1 to 6 mm, and spectral width of the reporter molecules ranging from 16 &#181;T (160 mG) to 5 mT (50 G). A cross-loop bimodal resonator decouples excitation and detection, reducing the noise, while the rapid scan effect allows more power to be input to the spin system before saturation, increasing the EPR signal. This leads to a substantially higher signal-to-noise ratio than in conventional CW EPR experiments.

Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo

A new electron paramagnetic resonance (EPR) method, rapid scan EPR (RS-EPR), is demonstrated for 2D spectral spatial imaging which is superior to the traditional continuous wave (CW) technique and opens new venues for in vivo imaging. Results are demonstrated at 250 MHz, but the technique is applicable at any frequency.

We demonstrate a superior method of 2D spectral-spatial imaging of stable radical reporter molecules at 250 MHz using rapid-scan ...

Magnetic Levitation Coupled with Portable Imaging and Analysis for Disease Diagnostics

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for specialized equipment and trained personnel require that many diagnostic tests be performed at remote, centralized clinical laboratories. Magnetic levitation is a simple yet powerful technique and can be applied to levitate cells, which are suspended in a paramagnetic solution and placed in a magnetic field, at a position determined by equilibrium between a magnetic force and a buoyancy force. Here, we present a versatile platform technology designed for point-of-care diagnostics which uses magnetic levitation coupled to microscopic imaging and automated analysis to determine the density distribution of a patient's cells as a useful diagnostic indicator. We present two platforms operating on this principle: (i) a smartphone-compatible version of the technology, where the built-in smartphone camera is used to image cells in the magnetic field and a smartphone application processes the images and to measures the density distribution of the cells and (ii) a self-contained version where a camera board is used to capture images and an embedded processing unit with attached thin-film-transistor (TFT) screen measures and displays the results. Demonstrated applications include: (i) measuring the altered distribution of a cell population with a disease phenotype compared to a healthy phenotype, which is applied to sickle cell disease diagnosis, and (ii) separation of different cell types based on their characteristic densities, which is applied to separate white blood cells from red blood cells for white blood cell cytometry. These applications, as well as future extensions of the essential density-based measurements enabled by this portable, user-friendly platform technology, will significantly enhance disease diagnostic capabilities at the point of care.

We present a magnetic levitation technique coupled with automated imaging and analysis in both a smartphone-compatible device and a device with embedded imaging and processing. This is applied to measure the density distribution of cells with two demonstrated biomedical applications: sickle cell disease diagnosis and separating white and red blood cells.

Currently, many clinical diagnostic procedures are complex, costly, inefficient, and inaccessible to a large population in the world. The requirements for ...

Metabolic Support of Excised, Living Brain Tissues During Magnetic Resonance Microscopy Acquisition

This protocol describes the procedures necessary to support normal metabolic functions of acute brain slice preparations during the collection of magnetic resonance (MR) microscopy data. While it is possible to perform MR collections on living, excised mammalian tissue, such experiments have traditionally been constrained by resolution limits and are thus incapable of visualizing tissue microstructure. Conversely, MR protocols that did achieve microscopic image resolution required the use of fixed samples to accommodate the need for static, unchanging conditions over lengthy scan times. The current protocol describes the first available MR technique that enables imaging of living, mammalian tissue samples at microscopic resolutions. Such data is of great importance to the understanding of how pathology-based contrast changes occurring at the microscopic level influence the content of macroscopic MR scans such as those used in the clinic. Once such an understanding is realized, diagnostic methods with greater sensitivity and accuracy can be developed, which will translate directly to earlier disease treatment, more accurate therapy monitoring and improved patient outcomes.
While the described methodology focuses on brain slice preparations, the protocol is adaptable to any excised tissue slice given that changes are made to the gas and perfusate preparations to accommodate the tissue&#39;s specific metabolic needs. Successful execution of the protocol should result in living, acute slice preparations that exhibit MR diffusion signal stability for periods up to 15.5 h. The primary advantages of the current system over other MR compatible perfusion apparatuses are its compatibility with the MR microscopy hardware required to attain higher resolution images and ability to provide constant, uninterrupted flow with carefully regulated perfusate conditions. Reduced sample throughput is a consideration with this design as only one tissue slice may be imaged at a time.

The current protocol describes a method by which users can maintain viability of acute hippocampal and cortical slice preparations during the collection of magnetic resonance microscopy data.

This protocol describes the procedures necessary to support normal metabolic functions of acute brain slice preparations during the collection of magnetic ...

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

This paper elaborates the sample preparation protocols required to obtain optimal domain patterns using the Bitter method, focusing on the extra steps compared to standard metallographic sample preparation procedures. The paper proposes a novel bespoke rig for dynamic domain imaging with in situ BH (magnetic hysteresis) measurements and elaborates the protocols for the sensor preparation and the use of the rig to ensure accurate BH measurement. The protocols for static and ordinary dynamic domain imaging (without in situ BH measurements) are also presented. The reported method takes advantage of the convenience and high sensitivity of the traditional Bitter method and enables in situ BH measurement without interrupting or interfering with the domain wall movement processes. This facilitates establishing a direct and quantitative link between the domain wall movement processes&#8211;microstructural feature interactions in ferritic steels with their BH loops. This method is anticipated to become a useful tool for the fundamental study of microstructure&#8211;magnetic property relationships in steels and to help interpret the electromagnetic sensor signals for non-destructive evaluation of steel microstructures.

Optimized Setup and Protocol for Magnetic Domain Imaging with In Situ Hysteresis Measurement

This paper elaborates the sample and sensor preparation procedures and the protocols for using the test rig particularly for dynamic domain imaging with in situ BH measurements in order to achieve optimal domain pattern quality and accurate BH measurements.

This paper elaborates the sample preparation protocols required to obtain optimal domain patterns using the Bitter method, focusing on the extra steps ...

Hand-held Clinical Photoacoustic Imaging System for Real-time Non-invasive Small Animal Imaging

Translation of photoacoustic imaging into the clinic is a major challenge. Handheld real-time clinical photoacoustic imaging systems are very rare. Here, we report a combined photoacoustic and clinical ultrasound imaging system by integrating an ultrasound probe with light delivery for small animal imaging. We demonstrate this by showing sentinel lymph node imaging in small animals along with minimally invasive real-time needle guidance. A clinical ultrasound platform with access to raw channel data allows the integration of photoacoustic imaging leading to a handheld real-time clinical photoacoustic imaging system. Methylene blue was used for sentinel lymph node imaging at 675 nm wavelength. Additionally, needle guidance with dual modal ultrasound and photoacoustic imaging was shown using the imaging system. Depth imaging of up to 1.5 cm was demonstrated with a 10 Hz laser at a photoacoustic imaging frame rate of 5 frames per second.

A clinical handheld photoacoustic imaging system will be demonstrated for real-time non-invasive small animal imaging.

Translation of photoacoustic imaging into the clinic is a major challenge. Handheld real-time clinical photoacoustic imaging systems are very rare. Here, ...

Magnetic-, Acoustic-, and Optical-Triple-Responsive Microbubbles for Magnetic Hyperthermia and Pothotothermal Combination Cancer Therapy

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has been challenged. Here, we fabricate iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. Iron oxide nanoparticles serve as both magnetic and photothermal agents. Once intravenously injected, NSMs can be magnetically guided to the tumor site. Ultrasound triggers the release of iron oxide nanoparticles, facilitating the penetration of nanoparticles deep into the tumor due to the cavitation effect of microbubbles. Thereafter, magnetic hyperthermia and photothermal therapy can be performed on the tumor for combinational cancer therapy, a solution for cancer resistance due to the tumor heterogeneity. In this protocol, the synthesis and characterization of NSMs including structural, chemical, magnetic and acoustic properties were performed. In addition, the anti-cancer efficacy by thermal therapy was investigated using in vitro cell cultures. The proposed delivery strategy and combination therapy holds great promise in cancer treatment to improve both delivery and anticancer efficacies.

Presented here is a protocol for the fabrication of iron oxide nanoparticle-shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform for magnetic hyperthermia and photothermal combination cancer therapy.

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has ...

Quantification of Mouse Heart Left Ventricular Function, Myocardial Strain, and Hemodynamic Forces by Cardiovascular Magnetic Resonance Imaging

Mouse models have contributed significantly to understanding genetic and physiological factors involved in healthy cardiac function, how perturbations result in pathology, and how myocardial diseases may be treated. Cardiovascular magnetic resonance imaging (CMR) has become an indispensable tool for a comprehensive in vivo assessment of cardiac anatomy and function. This protocol shows detailed measurements of mouse heart left ventricular function, myocardial strain, and hemodynamic forces using 7-Tesla CMR. First, animal preparation and positioning in the scanner are demonstrated. Survey scans are performed for planning imaging slices in various short- and long-axis views. A series of prospective ECG-triggered short-axis (SA) movies (or CINE images) are acquired covering the heart from apex to base, capturing end-systolic and end-diastolic phases. Subsequently, single-slice, retrospectively gated CINE images are acquired in a midventricular SA view, and in 2-, 3-, and 4-chamber views, to be reconstructed into high-temporal resolution CINE images using custom-built and open-source software. CINE images are subsequently analyzed using dedicated CMR image analysis software.
Delineating endomyocardial and epicardial borders in SA end-systolic and end-diastolic CINE images allows for the calculation of end-systolic and end-diastolic volumes, ejection fraction, and cardiac output. The midventricular SA CINE images are delineated for all cardiac time frames to extract a detailed volume-time curve. Its time derivative allows for the calculation of the diastolic function as the ratio of the early filling and atrial contraction waves. Finally, left ventricular endocardial walls in the 2-, 3-, and 4-chamber views are delineated using feature-tracking, from which longitudinal myocardial strain parameters and left ventricular hemodynamic forces are calculated. In conclusion, this protocol provides detailed in vivo quantification of the mouse cardiac parameters, which can be used to study temporal alterations in cardiac function in various mouse models of heart disease.

This study describes a comprehensive cardiovascular magnetic resonance imaging (CMR) protocol to quantify the left ventricular functional parameters of the mouse heart. The protocol describes the acquisition, post-processing, and analysis of the CMR images as well as assessment of different cardiac functional parameters.

Mouse models have contributed significantly to understanding genetic and physiological factors involved in healthy cardiac function, how perturbations ...